In order to convey a multiplicity of individuals within a short time by means of an elevator installation, it is known from international laid-open application WO 2004/048243 A1 to arrange at least two elevator cars one above another in a shaft and to move same upward and downward vertically separately from each other. Each elevator car is assigned a driving device with a drive pulley, with the aid of which the elevator car can be driven. The two elevator cars can be moved upward and downward along a common track in the shaft.
The two elevator cars are each connected to a counterweight via a rope or belt arrangement. At least one rope or belt arrangement here has two rope or belt sections via which one of the two elevator cars is coupled to the counterweight thereof and which run along at least one side of the other elevator car. For example, provision may be made for the second elevator car, which is arranged below the first elevator car, to be suspended on two supporting rope or supporting belt sections via which the second elevator car is coupled to the second counterweight and which extend upward vertically from the second elevator car and each run along a side of the first elevator car, and therefore the first elevator car is positioned between the two supporting rope or supporting belt sections of the second elevator car.
Elevator installations with two elevator cars which are arranged one above another in a shaft and are movable separately from each other are used in particular in the case of very high buildings. In these cases, the rope or belt arrangements have very great lengths. In this connection, the rope or belt arrangements may be induced into oscillations which are caused, for example, by a movement of the building in which the elevator installation is installed. Building movements of this type can occur because of wind loads or, for example, also in the event of an earthquake. The oscillations lead to deflections of the rope or belt arrangements in the horizontal direction. There is the risk in this case of rope or belt sections which run laterally along an elevator car coming into contact with the elevator car. This may lead to damage to the elevator car or else of the rope or belt sections. Furthermore, the contact with the elevator car causes the production of noises which may unsettle the passengers in the elevator car.
Accordingly, there is a need for an elevator installation of the type discussed above which prevents or minimizes the occurrence of oscillations in the rope or belt section, which may otherwise impair the elevator car.